Major cell types of the lung and skin are being isolated and studied for their metabolisms of xenobiotics and selected lipids (in comparison with liver cells). Special studies are being made with Clara, type II and ciliated cells of the lung and sebaceous and basal cells of the skin. Studies of the effects of the techniques used in isolating the enriched populations of cells from tissues are being made with various antibodies to selected cytochrome P-450 isozymes and Western blotting/microdots for quantifying these isozymes and related peptides in cells at various stages in the isolation procedures. A microspectrophotofluorometer is being used to quantify xenobiotic metabolism in single cells and to study variations in this metabolism among cells of a homogenous population. Variations in enzyme activity in periportal and centrolobular liver cells in the perinatal period are compared with these activities in the adult liver. Isolated skin cells are being used to study the metabolism of prostaglandins and arachidonic acid and the site of accumulation of lipid soluble chemicals like the PCBs.